This invention employs the thorough mixture of X-form and/or Y-form oxo-titanyl phthalocyanine and titanium dioxide as the photosensitive material of a photoconductive element. This mixture provides improved dark decay and control of sensitivity. Both oxo-titanyl phthalocyanine and titanium dioxide are known photoconductors, but are not known to provide exceptional functioning when combined. As it is well known, the X-form and Y-form material differ from each other by their crystalline structure, as well as from other crystalline forms of oxo-titanyl phthalocyanine as evidenced by their different X-ray diffraction patterns. They are often referred to as "pigments" even when used as photoconductors.
The addition of alumina to metal-free phthalocyanine and vanadyl phthalocyanine to enhance photoconductivity is reported by Saito et al. in an article entitled "Photocarrier Generation Process of Phthalocyanine Particles Dispersed in a Polymer: Effects of Pigment Particle Size, Polymer Matrix and Addition of Fine .gamma.-Alumina Particles," in Japanese Journal of Applied Physics, Vol. 30. No. 7A, July, 1991, pp. L 1182-L 1185.
Phthalocyanine green and phthalocyanine blue (neither of which are X-form or Y-form oxo-titanyl phthalocyanine) are employed together with titanium dioxide in U.S. Pat. Nos. 5,069,992 to Leyrer et al.; 4,268,597 to Klavan et al.; and 4,202,620 to Klavan et al. Phthalocyanine and titanium are employed in separate migration layers in U.S. Pat. No. 3,982,939 to Bean. U.S. Pat. No. 3,899,329 to Bean et al. discloses photosensitive members which have a mixture of photoconductive materials, but not a unique, previously unutilized combination of known photoconductive materials such as X-form or Y-form oxo-titanyl phthalocyanine and titanium dioxide, to achieve improved photoconductive characteristics.